This invention relates in general to land vehicles and more particularly, to personal mobility vehicles. Most particularly, the invention relates to camber assemblies for wheelchairs.
Frequently, the rear wheels of a wheelchair are cambered, or angled with respect to a vertical plane. A wheelchair with a large camber angle has more responsive turning, and is typically beneficial in sports applications. A wheelchair with little to no camber has a smaller overall width and thus increased maneuverability in tight confines. Wheelchairs with adjustable camber are well known in the art. Adjustable camber allows the user to change the camber angle in order to adapt to a driving environment. A user would typically choose a small camber angle for indoor use, and a large camber angle for outdoor use. Changing camber alters several characteristics of the wheelchair due to the repositioning of the wheels. One undesirable consequence of changing from no camber to a high camber angle is that the rear of the wheelchair is lowered. This lowering not only alters the user's position, but also requires the front casters to be re-squared. Re-squaring the front casters is often a difficult adjustment. Another undesirable result of adjustable camber is that the tops of the rear wheels tend to tilt inward towards the centerline of the wheelchair, which changes the location of the tires and hand rims. To compensate for these changes, the rear axles must displace outward and downward as the camber angle increases. There are several wheelchairs available that offer two or more camber angles while addressing these issues with limited success. One such wheelchair is described in U.S. Pat. No. 6,311,999. In this invention, the height of the rear of the wheelchair changes as the camber angle is changed, requiring that the front casters be re-squared during such adjustment.
What is needed is a wheelchair that offers the user a wide range of camber angles, is quickly and easily adjusted without having to re-square the casters, and that compensates for the change in position of the wheel.